Aircraft



Aug. 15, 1933. J. H. cRosMAN, aD

AIRCRAFT Filed May 16, 1932 2 Sheets-Sheet l 8.15, 1933- J. H. CROSMAN, 30 1,922,124

- AIRCRAFT I Filed ma 16, 1952 2 Sheets-Sheet 2 immmmml WHE 15 no actual, propelling power at or near the hub no material p Of the invention- Patentecl Aug. 15, e t t UNITED. STATES: PATENT OFFICE AIRCRAFT v James Heronbrosman, 3d, Wilmington, N. it Ap plication Maylfi, 1932. serialjNo. 611,691

10 cams. (01. 170-159) This invention relates to aircraft, and has for Fig. 4 is a front elevation of the. operative and its object to reduce air resistance to the forward novel element of the invention, and

movement of such craftwhereby the speed of Fig. 5 is abo om p n V w o the same at a' given number of revolutions per Referring to the drawings, in which like refminute of the propeller may be materially in erence numerals indicate like parts throughout creased, or the number of revolutions required the several views, 1 indicates any suitable proto maintain a givenspeed' may be decreased. peller shaft, and 2 a propeller secured thereto It is known that'when an aeroplane is moving in any suitable way. As here shown, the shaft at any considerable speed, a compacted body of 1 has a flange 3 n the forward end thereof to 1 air is built up immediately in frontof the hub which flange t e p opeller is secured by mea s portion of the propeller shaft, which compacted of bolts 4 passing through the u o the P body. of ir offers a very material resistance to p l and said fla h p p l its y the I f ward. movement ofithe aircraft s a be of any suitable or desired construction, such whole. .Generally speaking, the propeller ha specific construction of the propeller forming and: the air at or near said hub is not driven Secured 0 the forward end of the p 'ep le rearward; by themotion of the propel1er,. as is Shaft in y suitable man f t reversely the case at some radial distance outward from cu longitudinally eXtel-ldingportiohs of V th h he t p n blades t p n t a hollowcone, made 'of metal or other. suitable air to impart rearward motion thereto. ,Hereto- 'm t said portion being connected 7 ,35 pendicular to its base, Said COnepoI-tmns 59m may be secured in any practical or desired form fore many efforts have been made to eliminate gethel pp oxi a y in the line of the axis of or materially reduce this body of compacted the propeller Shaft a n @1355 S as air in front of the hub or the forward end, of Shown in Fig 3, a section will hav approxthe. propeller shaft,. but so fara's I, am aware, m the form f e letter 8. These two 26 none of these for various reasons. have been 9011118911861 reVerSely Curved e p ons are so deemed practical. By means of the presentfin- Secured in any Suitable y to the forward end vention it has been found that the speed oflan 0f e Propeller S AS here Shown y a e aircraft at a given number of revolutions per mounted 011 a a 6 h ch is Secured to the minute of the propeller is materially increased. front face of hub of the p er pref- 30 Generallystatedfthe invention consists in conl l y pe th bolts through the base meeting to the forward end of.- the propeller fir hub ofthe prope e an h fla e 3 shaft, either directly or indirectly, two. reversely of the a W e thls 1s a Practical method curved "longitudinally extending portions of a 0f mountlng the Dortlons o a ho ow cone, it is headstone, one element orwhich cone is perbe expressly n rs od ha such m n n joined along said perpendicular element and Without f tm m the sPlnt of the mven" connected at their base to the forward end of @1011, the m f t il bemg to m n these the propeller Shaft n h hollow conle portions upon the forward end of Theinventive idea is capable of vreceivinga g {32 2 anyfiultablf F t variety of mechanical expressionsoneof which, an Sal por Ions revo forthe purpose of illustrating the invention is Shaft Wlth the apex 7 5) thereofm lme shown in theiaccompanyin drawings butit is with Q R P fl and w g lr s understood a such drawings o w a :c l ?o 1 t?fe 5151 523 i r iga r :i to?;3 i /h at? 1 i i tg 1 da axial line of the propeller shaft. The reversely 190 .eslgne 0 e e S 9 e e r curved conical portions 55 are not portions of iQmI Q being had to the appended Claims a right cone, but are portions of a cone one ele- {for this purpose. u ment of which is perpendicular to itsbase, said "j In said drawingsportions beingjoined along said perpendicular .59 11 efperspeetive view of the nvention. element, which element lies, in the present con- Fig. 2 is, a plan view thereof parts being struction, substantially in the axis of the proshown in section- H 4 peller shaft. Preferably these cone sections are Fig.3. is a cross sectional view of oneelement not joined throughout their entire extent along or the invention, taken on the lines 3- 3 of said element, but are separated as shown at 10,

Fig. .5, by means of a narrow slotextending part way from the apex '7 rearward for a suitable distance toward the propeller. It has been found that said slot 10 may extend approximately two fifths of such distance. Preferably also the leading edges 8,8 of the reversely curved portions 5,5 extend from the base toward the apex '7 along lines slightly diverging when viewed as shown in Fig. 4, one of the edges appearing above the horizontal line connecting the bases of cone portions 5,5, shown in Fig. 4 and the other slightly below said horizontal line, and preferably, but not necessarily, the extreme forward ends or tips 11,11 ofsaid cone portions 5,5" do not extend to a sharp point but terminate slightly short the cone.

As shown in Fig. 1, the cone portions 5,5 are mounted on a propeller shaft which turns in a clockwise direction, as indicated by the arrows in said figure, and said cone sections are so formed that their forward edge portions 8,8 move in the direction of the arrows, as shown in Fig. 3, thatis, in the same direction as does the propeller shaft. Wherefa propeller shaft is employed, however, which revolves in a reverse direction, the leading edges 8,8 of the cone sections would be likewise reversed, the principle being that the edge portions 8,8 of the cone sections 5,5 are the leading portions of said sections.

As heretofore pointed out, when an aeroplane attains flying speed, a compact body of air is formed. in front of the propeller 'hub or shaft, but with the present device it has been found that such compact body of air apparently'is not thus for1ned. Whatever may be the correct theory of operation of the device, the fact remains that with this device in operation the speed of the aeroplane, at a given number of revolutions per minute of the propeller shaft, is very materially increased. An aeroplane may maintain a given desired speed with a material decrease in the amount of fuel and lubricating oil'consunied, thus materially decreasing the expense of operation of the aeroplane, both from the view of fuel saved and also from the decreased amount of the time of motor operation and the wearing of moving parts of the same.

While for the purposeof describing the invention the same has been shown and described indetail, it will be understood by those skilled in the art that various changes and modifications from the precise construction shown and described may be made without departing from the spirit of the invention. Thus, while the invention has been described specifically in connection with its employment in aeroplanes, the same is applicable to other forms of aircraft.

Having thus described the invention, what is claimed is: V

1. In a propeller of the class described, the combination of a propeller shaft, propeller blades connected to said shaft, and two reversely curved longitudinally extending portions of a hollow cone connected at their bases to and extending in front of the forward end of said shaft, the free edges of said cone portions being the leading edges thereof.

2. In a propeller of the class described, the combination of a propeller shaft, propeller blades connected to said shaft, and two reversely curved surfaces so connected together that they are substantially S-shaped in cross section, said surfaces being connected at their ba'sestoand extending in front of said shaft and tapering forof the apex '1 of wardly to a point approximately on the axial line of said shaft, the free edges of said curved surfaces being the leading edges when the said shaft is revolved.

3. In a propeller of the class described, the combination of a propeller shaft, propeller blades on said shaft, and two reversely curved longitudinally extending portions of a hollow cone one element of which cone is perpendicular to its base, said cone portions being joined along said perpendicular element and connected at theirbases to and extending in front of the forward end of said shaft, the free edges of said coneportions being the leading edges when the said shaft is revolved.

4. In "a propeller of the class described, the

combination of a propeller shaft, propeller blades on said shaft, a plurality of curved vanes secured to and extending in front of the forward end of said shaft, each of said vanes having a concave conical surface with one'element thereof perpendicular to the front face of the propeller shaft, said vanes being connected along a line substantially coincident with said'vertical element of said conical surfaces, the free edges of said vanes being the leading edges when the said shaft is revolved.

5. In a propeller of the class described, the combination of a propeller shaft, propeller blades on said shaft, a plurality of curved vanes secured to and extending in front of the forward end of said shaft, eachof said vanes having a concave conical surface with one element thereof perpendicular to the front face of the propeller shaft, said vanes being connected along a line substantially coincident with said vertical element of said conical surfaces and in the axial line of said shaft, the free edges of said vanes being'the leading edges when said shaft is revolved. e I

6. An attachment for the end of a propeller shaft comprising a base plate adapted 'to be secured to the end of said shaft, a plurality of curved vanes secured to said base plate, each of said vanes having a concave conical surface 120 with one element thereof perpendicular to said base plate, and a web connecting each of said vanes to the other, the line of connection of said vanes being substantially coincident with the vertical element of its conical surface, the 125 free edges of said vanes being the leading edges when said shaft is revolved.

7. In a propeller of the class described, an attachment for the end of a propeller shaft comprising a base plate adapted to be secured 130 to the end of said shaft, a plurality of curved vanes secured to said base plate, each of said vanes having a concave conical surface with one element thereof perpendicular to said base plate, and a web connecting each of said vanes to the other along the line of said perpendicular element from the base toward but not to the apex of said conical surfaces whereby a slot or line of division is left adjacent the apex, the free edges of said vanes being the leading edges when the said shaft is revolved.

8. In a propeller of the class described, the combination of a propeller shaft, propeller blades connected to said shaft, and two reversely curved longitudinally extending portions of a hollow'cone, one element of which cone is perpendicular to its base, said cone portions being joined throughout a portion of their length along said perpendicular element and connected at their bases to and extending in front of the forward end of the shaft, the free edges of said cone portions being. the leading edges when the said shaft is revolved.

9. In a propeller of the class described, the combination of a propeller shaft, propeller blades connected to said shaft, and two reversely curved longitudinally extending portions of 10. In a propeller of the class described, the combination of a propeller shaft, propeller blades on said shaft, and two reversely curved longitudinally extending portions of a hollow cone,one element of which cone is perpendicular to its base, said cone portions being joined along said perpendicular element and connected at their bases to the forward end of the propeller hub, said bases extending outward toward but not to the effective faces of the propeller blades, and the free edges of saidcone portions being the leading edges when the said shaft is revolved. J. HERON CROSMAN '3n. 

